Initial flame_lua_runtime package

lib/runtime/packages/stable_package_store.dart

@@ -0,0 +1,86 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+
+import '../game/runtime_options.dart';
+import 'game_package.dart';
+import 'game_package_manifest.dart';
+
+class StablePackageStore {
+  const StablePackageStore({
+    RuntimeOptions runtimeOptions = const RuntimeOptions(),
+  }) : _runtimeOptions = runtimeOptions;
+
+  final RuntimeOptions _runtimeOptions;
+
+  Future<Directory> cacheRoot() async {
+    final support = await getApplicationSupportDirectory();
+    final root = Directory(p.join(support.path, 'flame_lua_packages'));
+    root.createSync(recursive: true);
+    return root;
+  }
+
+  Future<Directory> versionDirectory(String gameId, String version) async {
+    final root = await cacheRoot();
+    return Directory(p.join(root.path, gameId, version));
+  }
+
+  Future<void> markStable(GamePackage package) async {
+    if (package.source != GamePackageSource.file) {
+      return;
+    }
+    final marker = await _markerFile(package.manifest.gameId);
+    marker.createSync(recursive: true);
+    final previous = await stablePackage(package.manifest.gameId);
+    final data = {
+      'current': package.rootPath,
+      if (previous != null && previous.rootPath != package.rootPath)
+        'previous': previous.rootPath,
+    };
+    marker.writeAsStringSync(const JsonEncoder.withIndent('  ').convert(data));
+  }
+
+  Future<GamePackage?> stablePackage(String gameId) async {
+    final marker = await _markerFile(gameId);
+    if (!marker.existsSync()) {
+      return null;
+    }
+    final data =
+        jsonDecode(await marker.readAsString()) as Map<String, Object?>;
+    return _packageFromPath(data['current']);
+  }
+
+  Future<GamePackage?> previousStablePackage(String gameId) async {
+    final marker = await _markerFile(gameId);
+    if (!marker.existsSync()) {
+      return null;
+    }
+    final data =
+        jsonDecode(await marker.readAsString()) as Map<String, Object?>;
+    return _packageFromPath(data['previous']);
+  }
+
+  Future<File> _markerFile(String gameId) async {
+    final root = await cacheRoot();
+    return File(p.join(root.path, gameId, 'stable.json'));
+  }
+
+  GamePackage? _packageFromPath(Object? pathValue) {
+    if (pathValue is! String || pathValue.isEmpty) {
+      return null;
+    }
+    final manifestFile = File(p.join(pathValue, 'manifest.json'));
+    if (!manifestFile.existsSync()) {
+      return null;
+    }
+    return GamePackage.file(
+      rootPath: pathValue,
+      manifest: GamePackageManifest.fromJsonString(
+        manifestFile.readAsStringSync(),
+      ),
+      runtimeLuaRoot: _runtimeOptions.runtimeLuaRoot,
+    );
+  }
+}